RFR: 8316056: Open source several Swing JTree tests

[Damon Nguyen]

These are the tests being converted:

javax/swing/JTree/4210432/bug4210432.java
javax/swing/JTree/4213868/bug4213868.java
javax/swing/JTree/4224491/bug4224491.java
javax/swing/JTree/4237370/bug4237370.java
javax/swing/JTree/4662505/bug4662505.java

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Commit messages:
 - Initial test conversion to open

Changes: https://git.openjdk.org/jdk/pull/15756/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15756&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316056
  Stats: 354 lines in 5 files changed: 354 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15756.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15756/head:pull/15756

PR: https://git.openjdk.org/jdk/pull/15756